Organic dyes with photophysical properties affected by alterations in the properties of the media, including viscosity, temperature, and polarity, are known as environment-sensitive probes. These probes are widely used in various areas of analytical, biological and material sciences. This poster will describe our initial efforts on designing multi-responsive environment-sensitive probes based on squaric acid scaffolds. Specifically, the incorporation of aminoquinoline moieties produced small molecule viscometers, which have the ability to sense polarity variations of organic solvents. Multiplexing abilities, coupled with modular and facile synthesis, distinguishes these probes from other types.

Many drugs today are small molecules and function through a specific binding with their target. This has proved to be efficient, yet the idea of larger macromolecules being used as drugs has grown more popular because of their flexibility. The issue with these larger molecules is that they have been previously difficult to synthesize. The emphasis of the research is to find an efficient way to synthesize macrocycles, reducing purification processes and side products. All reactions are done in solution and column chromatography is used to purify. An important aspect is testing if this cyclization method is possible with all amino acids or if limitations are present based on the backbone of the molecule. Because macrocycles have proved difficult to synthesize in the past, they are overlooked in the field of drug design. However, with this rather basic process it is possible to create new rules associated with drug design and defy what was once believed about macrocycles.

Organic synthesis and research into the activity and uses for macrocycle compounds have increased in recent years. These compounds proved to be an interesting field of research due to their size and ability to orient in different ways depending on the environment. The synthesis of these molecules is done by using a stable foundation molecule, cyanuric chloride, which is subject to substitution. The compound can be built from there using nucleophilic substitution with various nitrogen-based compounds. Then, in the final steps of the synthesis, the compounds dimerize forming the macrocycle. The amino acid nucleophile used to build the molecule is being varied to build many different compounds. The challenge, however, is to find the most efficient route for synthesis. I have successfully managed to synthesize one macrocycle compound using lysine with a Z protecting group as the starting material. Throughout the synthesis there was great difficulty with the compound’s solubility, therefore the starting material was switched to a BOC protected lysine amino acid. This resulted in better solubility throughout the process and yielded another successful macrocycle. These results demonstrate how the synthesis pathway we used to build these macrocyclic dimers is successful, but the process can be variable, based on the properties of the amino acid. It is recognized how the synthesis of these compounds is only the first step and further research into the properties and actions of the compounds is necessary. However, a pure product and efficient synthesis in making the macrocycle is important to properly access its properties. My further research will specifically test the antibiotic properties, if any, the macrocycles possess.

The mis-regulation of reactive oxygen species (ROS) and transition metals contribute to the onset of Alzheimer’s Disease (AD). A tetra-aza macrocyclic pyridinophane with an indole moiety, (Ind)PyN3, was evaluated on its radical scavenging reactivity and ability to chelate and stabilize the copper (II) oxidation state; these evaluations contribute to the overall therapeutic efficacy of the ligand in treating AD. Compared to a congener replacing the indole moiety with a hydroxyl moiety, (OH)PyN3, (Ind)PyN3 displayed comparable radical scavenging reactivity to (OH)PyN3. The fluorometric CCA assay revealed that (Ind)PyN3 was able to the stabilize the copper (II) oxidation state and prevent it from generating ROS via redox cycling at both 1 and ½ equivalents, albeit (OH)PyN3 was more effective at copper (II) oxidation state stabilization than (Ind)PyN3 at half molar equivalence. Our results demonstrate that the addition of the indole moiety to a tetra-aza macrocyclic pyridinophane does not disrupt radical scavenging reactivity by the indole moiety nor the ability of the pyridinophane to stabilize transition metal ions, warranting future exploration of the indole moiety in therapeutic design for AD.

Dispersion interactions also known as van der Waals interactions are essential for everything from nanomaterials to organic chemistry to biological chemistry. Modeling that chemistry requires modeling van der Waals interactions. Approximations that start from “freshman chemistry” molecular orbital (MO) theory do not account for dispersion. For example, helium-helium interactions are unbound in molecular orbital theory as two electrons are placed in antibonding orbital, but in reality, the interactions are weakly bound and can form a liquid. We have developed a density functional theory method embodying MO theory and corrections. Dispersion corrections can be added to noncovalent interactions in order to model them by using a standard model with different parameters. By fitting these parameters, the accurate known bond energies of real noncovalent complexes can be reproduced.